The present invention relates to an apparatus co-acting with a vehicle steering wheel for detecting a sleeping or dozing driver and providing an alarm system for awaking the driver.
The prior art shows different devices, which function as sleep detectors for drivers of vehicles. In this regard U.S. Pat. No. 6,172,610 to Prus discloses a sleepy driver detection and alarm system, which includes contacts for measuring skin resistance, and is provided with a micro-controller for determining a baseline resistance. The alarm is sounded, waking the driver, when the resistance varies from the baseline. The arrangement is believed to be unreliable since the ambient temperature differences effect perspiration and will alter the skin resistance readings. U.S. Pat. No. 6,218,947 to Sutherland is directed to a sleep detector having a sensed capacity between the two plates on a steering wheel rim. When the driver""s fingertips are released from the steering wheel an alarm is sounded. U.S. Pat. No. 4,210,905 to Coons shows a plurality of switches arranged around a vehicle steering wheel. The switches remain open as long as the driver grasps the steering wheel, however if the driver loosens his grip on the steering wheel as he dozes the switch will close making a complete circuit that activates an alarm. The prior art solutions to detect a driver who is about to fall asleep are not reliably sensitive or repeatable.
This invention incorporates the use of a sensitive load cell to measure the driver""s grasp of the vehicles steering wheel, and using that value as a base line for detecting a driver""s sleepiness. The load cell utilized is a force transducer, which converts a force into an electric signal. The present load cell is used to measure compression applied by the user""s hands to a steering wheel. In effect, the steering mechanism would have the attribute of an electronic scale.
The detection and alarm system for a dozing or sleeping automobile driver of the present invention can be individualized so that each individual who grasps a steering wheel to operate a vehicle will establish a base line value of weight on the steering wheel which remains as that individual""s signature value. Consequently, any variations below that value will activate an alarm, which may be audible as well as visual. The detection means is a load cell which may take the form of a strain gage having a sensitive spring element that responds to direct stress, bending or shear caused by the driver""s firm grasp of an automobile steering wheel. In this connection, for example, the steering wheel could be zeroed when the ignition is turned on. The driver would then take hold of the steering wheel in a natural grip. The force applied to the steering wheel would then be placed in the memory of the apparatus.
It should be noted that the present detection system could be delayed in operation until the vehicle reaches higher speeds, such as 55 mph. Thus, the apparatus can be deployed at higher speeds in order to avoid serious accidents at such elevated speeds. It is also contemplated to provide an automatic reset of the detection and alarm system after ignition is started in the vehicle. The grasp of the driver can be quantitated and reported back to the driver and occupant by a visual and audible scale, setting up a positive feedback loop, in effect placing the driver in tune with the vehicle and the vehicle in tune with the driver.